Localization of inhibin alpha-, betaA- and betaB-subunits and aromatase in ovarian follicles with granulosa theca cell tumor (GTCT) in 6 mares.

The research investigates the localization of various inhibin subunits and aromatase in ovarian follicles of mares with granulosa theca cell tumor (GTCT), comparing it with follicles from healthy mares. The study finds distinctive immunohistochemical characteristics in the GTCT cases and suggests that these tumors may affect the production of specific hormones.

Methodology and Objectives

• The goal of this research was to understand the morphological changes and immunohistochemical characteristics in mares with granulosa theca cell tumor (GTCT).
• Researchers used immunohistochemical staining for determining the localization of inhibin subunits (alpha, betaA, betaB) and aromatase in the granulosa layer and theca layers of the ovarian follicles.
• Ovarian follicles were obtained from 6 mares diagnosed with GTCT and a control group of 4 healthy mares.

Findings in the GTCT Cases

• Inhibin alpha-subunit was found in the granulosa cells of all follicles of various sizes in all GTCT cases, and betaA-subunit was found in two GTCT cases in follicles of all sizes.
• In contrast, inhibin betaB-subunit and aromatase were not found in any of the GTCT cases.
• This pattern suggests that some mares with GTCT can secrete dimeric inhibin (also known as inhibin A), but none of the GTCT cases can secrete inhibin B.
• The absence of aromatase staining implies that testosterone is not being converted into the hormone estradiol in GTCT follicles because of the unavailability of aromatase enzyme.

Findings in the Control Cases

• In healthy mares, inhibin alpha-, betaA-, and betaB-subunits and aromatase were found in large and medium-sized follicles.
• However, inhibin betaA- and betaB-subunits and aromatase were not found in small-sized follicles of healthy mares.

Implications of the Study

• The study gives insight into the changes in inhibin subunits and aromatase localization in mares affected with GTCT.
• This could further help in understanding the tumor’s impact on the hormonal balance of mares and may offer clues for better diagnostic and treatment options in future.